Click on the following links. Please note these will open in a new window.

Normal Curve and Z-Scores 
https://www.youtube.com/watch?annotation_id=annotation_202153&feature=iv&src_vid=1xhCL5m4nI0&v=fXOS4Q3nJQY
Demonstrate the normal curve and how to calculate Z scores

Normal Curve
https://www.youtube.com/watch?v=cgxPcdPbujI
The Normal Distribution and the 68-95-99.7 Rule (the Empirical Rule)